Quote Originally Posted by Mike Wilde View Post
Is it a question of how to use this analyser, or just this is your first analyser, and you are not sure how thay work overall?

Besalar made/marketted a slew of analysers, and the more sophisticated ones allowed more than one 'personality' to be stored. Some times electronically, and sometiems just as multple gangs of potentiometers that could be bank switched in and out of the bridge balance circuit.

Are you interested in using this for color negative to print RA-4 process work, or as a general b&w darkroom tool?
I don't have the manual for the PM4L but I have one for the PM2M which is similar in everything except that the display for the 2M is analog and when in white channel it has scale for both time and density, The 4L display only time value in the white channel. Color channels are display in densities.
The response of the PMT (Photomultiplier Tube) is linear its output is routed thru a bunch of diode and turn to logarithmic response. I don't exactly know how they did it. This signal is then display on the meter. On the 4L the output once again converted back to linear when in the white channel via a Log to Linear IC.